Cable connector having strain relief

ABSTRACT

A cable connector which includes a concave housing having opposed planar sides and a relation between the planar sides and having a proximate opening and a distal opening and first and second interior axial walls. A cable extends through the proximate opening in the exterior wall of the concave housing toward the distal opening and diverges adjacent the distal opening of the housing into opposed first and second transverse cable extensions. A terminal block is mounted in the distal opening of the housing having first and second projections and each of the projections engage one of the interior axial walls of the housing and one of the transverse cable extensions. Metallic contacts also extend from the terminal block to be electrically connected to the transverse cable extensions.

This application is a 371 of PCT/US98/01876 Jan. 30, 1998 which claimsbenefit of 60/031/312 Jan. 30, 1997.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to electrical connectors and moreparticularly to cable connectors.

2. Brief Description of Prior Developments

FIG. 1 shows the current method of making a charger cable connector.This prior art charger cable connector kit includes a top cover 10, abottom cover 12, a V-90 male connector 14, a paddle board 16 and a cable18. It also includes lateral latches 20 and 22 and buttons 24 and 26. Toachieve the strain relief, a flexible grommet is molded onto the cable.

To grip the grommet, a two piece cover is used, that is closed aroundthe grommet, and secured by screwing or riveting the two coverstogether, trapping the grommet, the terminal block, and the cableconnector metal latches.

When the cable is pulled, the force is transmitted from the copperwires, through the insulation, to the grommet. The grommet thentransmits the force to the cover body. The cover body transmits theforce to the metal latches, which transmit the force to the body of themating connector which, for this connector, is located in the case of amobile telephone. This procedure avoids a situation in which force istransmitted to either the solder joints or the contacts.

The grommet does not prevent all forces from being transmitted to thesolder joints or contacts particularly when the cable is flexed.Sometimes, however, a paddle board is used to further relieve the forceswhich will be transmitted to an individual contact to spread the forcesover a larger number of electrically non-functional contacts.

The paddle board is used particularly with miniature connectors, wherethe strength and retention of the contact in the housing is smallcompared to the forces which can be applied to the cable in the use ofsuch a product.

Disadvantages of the above described apparatus are as follows.

The number of components used means a high investment in tooling, a highmaterial cost, and a labor intensive assembly process.

For a cable type B to work effectively, the adhesion between the copperwires and the insulation, and the insulation and the jacket, must beextremely high. Otherwise, when the cable is pulled, the insulation andjacket will stretch, and the force will be conducted via the copperwires direct to the solder joints and contacts, resulting in either abroken solder joint, or a displaced contact or paddle board, if used.

If, however, the cable is made with very high insulation and jacketadhesion, it becomes very difficult to strip during the assemblyprocess, and becomes less flexible, making it less user friendly for theend user.

It is an object of the present invention to provide a cable connectorwhich avoids the above described disadvantages.

SUMMARY OF THE INVENTION

The present invention is a cable connector assembly which includes aconcave housing comprising a proximate cable receiving opening and adistal terminal block opening and an interior retaining block engagementmeans. A cable extends axially through the proximate cable receivingopening into the concave housing. A transverse cable extension isadjacent the distal block opening. A terminal block has an axialprojection and a metallic contact and is mounted in the distal retainingblock opening of the concave housing such that the projection engagesthe interior block retaining means and the projection and contact engagethe transverse cable extension.

Preferably, the terminal block has a primary strain relief groove, whichthe wire is placed into from above. The plastic housing squeezes theinsulation of the wires onto the copper, holding the wire into positionin the terminal block. This holds the parts in position while the wireis soldered to the contact, and also functions as a strain relief,isolating forces from the solder joint.

Further, when the housing is preferably fitted to the terminal block, bysliding it forward, a ramp in the cover pushes a secondary strain relieftongue towards the cable, and finally clamps the cable insulation (orjacket in the case of cable type B) firmly to the housing. Plastic barbsin the secondary strain relief tongue also exert a locally high pressureto the cable jacket, clamping the jacket to the insulation, to thecopper wires.

The housing is also preferably held in position against the terminalblock by means of a latching device. The housing is shaped at the backto provide an area where the cable is restrained in a straight length,so that any cable flexing forces will only be seen as an axial force atthe point where the cable is clamped to the cover. Further, the cableexit portion of the housing is provided with a radiused edge, to avoidany cutting of the cable jacket by repeated flexing.

The housing also preferably incorporates plastic latches, which willtransmit the forces from the cable to the mating connector. The plasticlatches are molded with a bias, and are squeezed inwards while the coveris assembled to the terminal block. When the latches are released, theflanges on each side of the main latch body rest against pre-load guidein the terminal block. This ensures that the latches always have apre-load force holding them against the terminal block, thus eliminatinga large part of the effect of manufacturing tolerances on the latchdepression force.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described with reference to theaccompanying drawings in which:

FIG. 1 is an exploded perspective view of a prior art charger cableconnector kit;

FIG. 2 is a perspective view of a disassembled cable connectorrepresenting a preferred embodiment of the present invention;

FIG. 3 is a perspective view of a disassembled cable connector assemblyrepresenting another preferred embodiment of the present invention;

FIG. 4 is a top cutaway perspective view of the assembled cableconnector shown in FIG. 2;

FIG. 5 is a side cutaway perspective view of the assembled cableconnector shown in FIG. 2;

FIG. 6 is a side cutaway perspective view of the assembled cableconnector shown in FIG. 5;

FIG. 7 is a plan cutaway view of the assembled cable connector shown inFIG. 6;

FIG. 8 is a cross sectional view through 8—8 in FIG. 7;

FIG. 9 is a detailed view of circle 9 in FIG. 8;

FIGS. 10a-10 d are perspective views illustrating steps in the method ofassembling the cable connector shown in FIGS. 2-4; and

FIGS. 11a-11 d are perspective views illustrating steps in the method ofassembling the cable connector shown in FIGS. 5-9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2-9, the connector assembly includes a concavehousing 28 which has a planar top side 30, a planar bottom side 32 whichare connected by vertical medial wall 34. In this housing there isproximate opening 36 and a transverse distal opening 38.

Referring particularly to FIG. 7, the housing also includes an axialinterior wall 40 which has a transverse projection 42 and a secondspaced axial interior wall 44 which has a transverse projection 46. Thehousing also includes a third axial interior wall 48 and a proximateopening seal 50. There are also lateral latches 52 and 54.

Referring particularly to FIGS. 8 and 9, the housing has a lowerinterior inclined surface 56 and an upper interior surface 58. Thislower interior surface 56 may be considered to be an actuator ramp as isfurther explained hereafter.

Referring to FIGS. 2-4, in the first embodiment of the connectorassembly, there is a cable type A which is shown generally at numeral60. This cable type A includes a conductor 62 with surroundinginsulation 64 and a second conductor 61 with its surrounding insulation68. At the distal end of the cable 60 type A it has a transverseextension 70 with a solder tail 72 and an opposed transverse extension74 with its solder tail 76.

Referring to FIGS. 5-9, the second embodiment of the cable connector isshown. It will be understood that this embodiment is essentiallyidentical to the first embodiment except that there is a minoradaptation to accommodate the inclusion of a cable type B which is showngenerally at numeral 78. This cable type B includes four conductors 80,82, 84 and 86 and their respective insulation layers 88, 90, 92 and 94and an outer cable jacket 95. At its terminal end the cable type B hasparallel transverse extensions 96 and 98 and their respective soldertails 100 and 102. In the opposed direction the cable type B also hasparallel transverse extensions 104 and 106 and their respective soldertails 108 and 110.

Referring again generally to FIGS. 2-9, both embodiments include aterminal block shown generally at the numeral 112. It will be understoodfrom the following description that these terminal blocks areessentially identical except for a minor accommodation necessary toengage the additional set of transverse extensions in the cable type B.The blocks each have an axial projection 114 with a lateral extension116 and a spaced parallel axial projection 118 which also has a lateralextension 120.

Referring particularly to FIG. 7, it will be seen that the lateralextension 116 on projection 114 engages transverse projection 42 on theaxial interior wall 40 of the concave housing. It will also be seen thatthe lateral extension 120 on axial projection 118 engages the lateralprojection 46 on the axial interior wall 44. On both embodiments of theconnector cable there is a transverse groove 122 on projection 114 whichengages a transverse extension of the cable. On the cable type Bembodiment there is also a second transverse groove 124 which engagesthe second parallel transverse extension of the cable type B. Similarly,in both embodiments there is a transverse groove 126 on projection 118which engages the opposed transverse extension of the cable and in thecable type B embodiment there is a second groove 128 which engages thesecond parallel transverse extension. The terminal block also includescontacts 130 and 132 which are electrically connected to the soldertails of the transverse extensions of the cables.

Referring particularly to FIG. 8, the terminal block has distal openingsas at opening 134 to allow electrical connection to the contacts as at130 from the opposed side of the terminal block.

Referring particularly to FIGS. 2 and 5, it will also be seen adjacentgrooves 122 and 124 there are convex primary strain relief features 136and 138 for the transverse extensions of the cable. Similarly, adjacentgrooves 126 and 128 there are primary strain relief features 140 and 142which serve the same purpose for the transverse cable extensions in theopposed direction.

Referring again to FIGS. 2-9 generally, it will be seen that theterminal block also includes an axial tongue 144 which extends into theconcave housing. This tongue 144 has a pair of spaced transverse barbs146 and 148 which serve as secondary strain relief features as isfurther explained as follows.

Referring particularly to FIGS. 8 and 9, it will be seen that thistongue 144 is interposed between the cable 78 and the lower interiorinclined surface 56 of the housing in contacting relation with both thelower surface of the housing and the cable. (While not shown with cable60, it will be understood that the same arrangement is used with thatcable.) It will also be seen that the barbs 146 and 148 grip theinsulative layer of the cable to affect a secondary strain relieffunction. Referring particularly to FIGS. 2-6 it will be seen that theterminal block also includes latch guide grooves 150 and 152 forreceiving, respectively, latches 52 and 54.

Referring to FIGS. 10a-11 d, a method for assembling the cable connectorof the present is illustrated. In FIGS. 10a-10 d the assembly of thecable type A embodiment is illustrated. The assembly of the cable type Bis illustrated in FIGS. 11a-11 d. Except for this difference, however,the two embodiments of this method are essentially identical.

Referring to FIGS. 10a and 11 b, in the first step of this method theconcave housing 28 is slid over either the cable type A 60 (FIG. 10a) orthe cable type B 78 (FIG. 11a). In FIGS. 10b and 11 b the second step ofthe method is illustrated in which the cable is stripped and its wiresare spread to form transverse extensions 70 and 74 (FIG. 10b) ortransverse extensions 70, 74, 76 and 78 (FIG. 11b). In FIG. 10c, thethird step in assembling the cable type A embodiment is shown in whichthe transverse extensions 70 and 74 are positioned in the transversegrooves 122 and 126 of projections 114 and 118. In this step the soldertails 72 and 76 are also connected to the contacts 130 and 132.Similarly, in FIG. 11c the third step in assembling the cable type Bembodiment is shown in which the transverse extensions 70, 74, 96 and 98are positioned in the grooves 122, 124, 126 and 128 and the solder tails72 and 100 are connected to contact 130 while solder tail 76 and 102 areconnected to contact 132. The final step of this method is illustratedin FIGS. 10d and 11 d in which it is shown that the lateral latches 52and 54 on the housing are squeezed inwardly so as to allow them to slidein the pre-load guides of the terminal block. This action causes thehousing to slide over the terminal block and causes the terminal blockprojections 114 and 118 to engage the interior walls 40 and 42 in theway shown in FIG. 7. This action also causes the tongue 114 to engagethe cable as at 78 and the lower interior inclined surface 56 in the wayshown in FIGS. 8 and 9.

It will be appreciated that a cable connector has been provided whichreduces the number of components, integrating the function of strainrelief into the terminal block, and providing a secondary strain reliefwhich is actuated by the cover during the assembly process.

It will also be appreciated that the cable connector described hereinwill be particularly useful for mobile I/O uses.

Those skilled in the art will appreciate that this invention may beapplicable to other types of devices. In particular, an aluminum cableor a flat ribbon cable or any combination of flat and round cables maybe substituted for the copper cable. It will also be appreciated thatthe fixture and holding means described herein may be applicable tooptical cables and optical wave guides.

While the present invention has been described in connection with thepreferred embodiments of the various figures, it is to be understoodthat other similar embodiments may be used or modifications andadditions may be made to the described embodiment for performing thesame function of the present invention without deviating therefrom.Therefore, the present invention should not be limited to any singleembodiment, but rather construed in breadth and scope in accordance withthe recitation of the appended claims.

What is claimed is:
 1. A cable connector comprising: (a) a concavehousing comprising opposed planar sides and an exterior wall extendingin normal relation between the planar sides and having a proximateopening and a distal opening and first and second interior axial walls;(b) a cable extending through the proximate opening in the exterior wallof the concave housing toward the distal opening and diverging adjacentthe distal opening of the housing into opposed first and secondtransverse cable extensions; and (c) a terminal block mounted in thedistal opening of the housing having first and second strain reliefprojections each of said projections engaging one of the interior axialwalls of the housing and one of the transverse cable extensions.
 2. Thecable connector of claim 1 wherein first and second metallic contactsextend from the terminal block and said first and second metalliccontacts are electrically connected respectively to the first and secondtransverse cable extensions.
 3. The cable connector of claim 2 whereinthe terminal block has at least one distal opening so as to allow accessto at least one of the metallic contacts.
 4. The cable connectorassembly of claim 1 wherein the distal opening is transverselyelongated.
 5. The cable connector assembly of claim 1 wherein theprojections of the terminal block each have at least one transversegroove which engages one of the transverse cable extensions.
 6. Thecable connector assembly of claim 5 wherein the projections of theterminal block each engage a plurality of transverse cable extensions.7. The cable connector assembly of claim 5 wherein the second interiorwall has a terminal lateral projection which engages a terminal lateralprojection on the second projection of the terminal block and the secondtransverse cable extension is engaged by said second projection.
 8. Thecable connector assembly of claim 1 wherein the first interior wall hasa terminal lateral projection which engages a terminal lateralprojection on the first projection of the terminal block and the firsttransverse cable extension is engaged by said first projection.
 9. Thecable connection assembly of claim 1 wherein a tongue extends from theterminal block in medial relation between said first and secondprojections to engage the cable.
 10. The cable connector assembly ofclaim 9 wherein one of the planar sides of the housing has an inclinedinner surface and the tongue bears against said inclined inner surface.11. The cable connector assembly of claim 10 wherein the inclined innersurface is inclined downwardly toward the distal opening.
 12. The cableconnector assembly of claim 11 wherein the tongue has at least one barbthat grips the cable.
 13. The cable connector assembly of claim 1wherein opposed lateral latching means fix the terminal block onto theconcave housing.
 14. A cable connector comprising: a concave housingcomprising a proximate cable receiving opening and a distal opening andan interior terminal block retaining means; a cable extending axiallythrough the proximate cable receiving opening into the concave housingand having a transverse cable extension adjacent the distal opening; aterminal block having a generally axial projection and being mounted inthe distal opening of the concave housing such that the axial projectionengages the interior block retaining means and the transverse cableextension; wherein a tongue extends from the terminal block into theconcave housing to engage the cable.
 15. A cable connector comprising: aconcave housing comprising a proximate cable receiving opening and adistal opening and an interior terminal block retaining means; a cableextending axially through the proximate cable receiving opening into theconcave housing and having a transverse cable extension adjacent thedistal opening; a terminal block having a generally axial projection andbeing mounted in the distal opening of the concave housing such thatstrain relief projections engage the interior block retaining means andthe transverse cable extension; wherein there is at least one metalliccontact and said contact is electrically connected to the transversecable extension; wherein there is a pair of spaced parallel strainrelief projections which extend into the housing to be fixed to theinterior terminal block retaining means.
 16. A method for assembling acable connector comprising the steps of: positioning a cable relative toa concave housing having a proximate opening and a distal opening and aterminal block engagement means such that the cable passes through saidproximate and distal openings; splitting said cable adjacent the distalopening of the housing to form a pair of opposed transverse cableextensions; positioning a terminal block having at least one axialprojection adjacent the distal opening of the housing and engaging atleast one of said cable extensions with the terminal block projection;causing the terminal block projection to be engaged with the terminalblock engagement means in the concave housing; wherein the terminalblock has a tongue which engages the cable.